Hydrocarbon fuel burning system and apparatus



Aug. 31 1937. A, T B SEY 2,091,581

HYDROCARBON FUEL BURNING SYSTEM AND APPARATUS Filed March 27, 1935 a Sheets-Sheet 1 INVENTOR AFT/l a! T, Bers'ey ATTORNEY Aug. 31, 1937. A. T. BERSEY 2,091,581

HYDRQCARBON FUEL BURNING SYSTEM AND APPARATUS Filed March 2'7, 1933 3 Sheets-Sheet 2 I65 269 /07 Z65 Z66 ,9

259 a 285 H8 25 /Z/ 24 232289 89 INVENTOR J E fi ffiU/ 75 17 WWW/ ATTORNEY Aug. 31, 1937. BERSEY 2,091,581

HYDROCARBQN FUEL BURNING SYSTEM AND APPARATUS Filed March 27, 1953 :s Sheets-Sheet s INVENTOR WWW/YA ATTORN EY Patented Aug. 31, 1 937 HYDROCARBON FUEL BURNING SYSTEM AND APPARATUS Arthur T. Betsey, Detroit, Mich, assignor to Kelvinator Corporation, Detroit, Mich a corporation of Michigan Application March 27, 1933, Serial No. 662,934

14 Claims. ((1158-28) The present invention relates to hydro-carbon fuel burning systems and apparatus and is a continuation in part of my co-pendlng application Serial No. 535,020 filed May 4, 1931, now

5 Patent No. 2,049,730, granted Aug. 4, 1936.

One of the objects of the present invention is to provide a fuel burning system, including control mechanism for causing fuel to be fed constantly to the burner at varying rates, l in accordance with the demand for heat from the burner, provided such demand is above a predetermined minimum, and for causing fuel to be fed intermittently at varying rates, in accordance with the demand for heat from the 15 burner, when the demand is below the predetermined minimum.

Another object of the invention is to provide .a fuel burning system and apparatus therefor in which system a room thermostat is used for n" controlling the pressure and consequently the quantity of fuel delivered to the burner and in which the variation of fuel pressure. is utilized for controlling the quantity of air delivered to the burner. A further object is to provide for a limited or pilot supply of fuel to the burner for maintaining the temperature of the burner above a certaln minimum during that phase of intermittent cycle of operation when fuel is not delivered to the burner for room, boiler etc. heating purposes.

Further objects and advantages will be apparent from the following description, reference being had to the accompanying drawings wherein preferred forms of embodiments are clearly shown.

In the drawings:

Fig. 1 is a perspective view of a furnace and my improved system applied thereto;

Fig. 2 is a diagrammatic view of the system;

Fig. 3 is a top plan view partly in section of the fuel and air regulator;

Fig. 4 is a sectional side view of the apparatus shown in Fig. 3;

Fig. 5 is a fragmentary view of the apparatus shown in Fig. 4 but in a different position;

Figs. 6 and '7 are sectional views taken on line |i-6 and 1-1 of Fig. 4.

Referring to the drawings in general and par- 5 ticularly to Figs. 1 and 2, there is shown a furnace 30 of the type used in houses for heating purposes. A burning apparatus generally indicated as 3| extends through the feed door of the furnace and is carried by a frame 33. This frame is swingingly supported on a pedestal 34.

A fuel supply line herein shown is an oil line 35 and a second fuel supply line 35 herein shown is a gas line and an electrical conduit 31 all extending through the pedestal .34 which is hollow for conveying fuels and electrical current 5 to the burning apparatus 3|. In the present case the burning apparatus is driven by a motor 39. Oil is fed to the burning apparatus from a tank 40 through the line 35. A shut ofl' valve 4| is provided in the oil line 35 which is to be used for preventing the flow of oil to the burner apparatus when it is desired to shutthe same off. The flow of oil through the line 35 is controlled by a float Valle 43, thermal responsive valve 44, a safety valve 45 and an accumulator forming a chamber or reservoir 45. A shut off valve 48 is interposed between the tank 40 and the float valve 43 for the purpose of shutting off the fuel when it is desired to inspect or repair valves 43, 44 and 45 or the accumulator 46. A limiting valve 49 is placed between the float valve 43 and the thermal responsive alve 44. The purpose of valve 49 is to prevent the flow of such a quantity of oil to the burner as to flood the same. Paralleling the valves 44, 45 and accumulator 46 is a pipe line 5| including a restricting valve 52. The purpose of pipe line 5| and valve 52 is to supply a limited quantity of oil to the burner for pilot purposes if an oil fuel is used as a pilot. The valves 44 and 45 are constructed in one housing. The valve 44 includes a bellows 54, and needle valve 55 which is arranged to control the flow of fuel through the passage 56. Bellows 54 is connected by a capillary tube with a room thermostat 53. This room thermostat is placed in the desired position in the living portion of the house and includes a casing 60 containing an expansible fluid such as alcohol. Variation in temperature of the air in the house will cause a variation in pressure in the casing 60 effecting a movement of the bellows 54 and needle valve 55. One wall of the casing 60 is flexible and is shown as comprising a metallic bellows 62. This flexible wall provides for increasing or decreasing the capac- 5 ity of the casing 60 and the flexible wall is moved by a hand operated screw 63. A spring 64 normally maintains the head of the bellows 65 in contact with the end of the screw 63. By manipulating the screw 63 the pressure within the casing 60 can be varied for the purpose of regulating the position of the needle valve so as to increase or decrease the quantity of fuel flowing in the oil line 35. Another portion of the wall of the casing 30 is made flexible to 55 take care of excessive high pressures in the casing whereby an excessive high pressure is not transmitted on the needle 55. This wall is in the form of a metallic bellows 61 which is loaded 5 with a spring 68 which will permit collapsing movement of bellows in the event of abnormal pressure.

The safety valve 45 includes a metallic bellows which actuates a needle II to control the 10 flow of oil through a passage I2. The interior of the bellows I0 is connected by a capillary tube I3 with the interior of a metallic bellows I4. Metallic bellows I4 is contained within a casing I5. Excessive pressure on the exterior of the bellows I4 will impart a collapsing movement thereof and a consequent expansion of bellows I0 so as to restrict or cut off the flow of oil through the passage 12. The purpose of the safety valve 45 and the bellows I4 is to limit or cut off the supply of fuel to the burner in case of an excessive temperature in the furnace. The pressure transmitted to the exterior of the bellows I4 may be created in any suitable manner, according to the type of furnace employed. In the present case a pipe I6 is connected to the boiler 11 of the furnace and therefore the bellows I4 is responsive to any excess pressure in the boiler due to overheating. A spring I9 within the bellows I4 normally tends to expand the same and this spring thereof. The pressure of the latter spring may be adjusted by a screw 8|.

The float valve 43 includes a float 82 which operates levers 83 which in turn actuate a needle valve 84 so as to maintain a constant level of fuel in the float valve casing 85. Fuel flowing from the tank passes the valve 48 and a strainer 81 whence the fuel flows through a passage 88 controlled by the needle valve 84. In this man- 40 ner a predetermined head of fuel is maintained above the thermal responsive valve 44.

If the needle valves 55 and 'II of valves 44 and are open, fuel will flow therethrough and into the accumulator 46. The accumulator includes 45 a stand pipe 90 which forms an inlet to the casing 9| and also includesan outlet in the form of a stand pipe 92. A syphon in the form of a capillary tube 93 has its inlet end of one leg 94 disposed a substantial distance below the tops of stand pipes 90 and 92 and has its outlet of the other leg 95 thereof within the stand pipe 9-2. At relatively cold temperatures the thermal control valve 44 is opened sufficiently to fill the casing 9| above the level of the stand pipe 92 whereby there is a constant flow of fuel from the stand pipe 90 into the casing 9| and out of the stand pipe 92. However, if the burners operate at milder temperatures in which the needle valve restricts the passage 56, the burner may consume the fuel n faster than it is supplied to the casing 9|. In that event, as the fuel level drops within the stand pipe 92 and consequently in the leg 95 of syphon 93, the fuel will be drawn through the capillary tube 93 and thereby lower the fuel level in the casing 9| down to the bottom of the leg 94.- After the fuel drops to this level, no more fuel will be withdrawn from the casing 9| until the fuel level in casing 9| again rises to the level of the stand pipes 90 and 92 at which time 7 the capillary tube will again function to supply a quantity of fuel to the burner. Thus in this manner in mild temperatures, fuel will be supplied intermittently to the burner.

The tank 40 is provided with a vent pipe 9'! for .fumes and vent pipes 98 and 99 are connected with the vent pipe 91 for dispelling fumes from the float valve 43 and the accumulator 46. It will also be noted that fuel can rise in the vent pipe 99.above the accumulator 46 for a purpose to be hereinafter described.

The fuel after passing the stand pipe 92 flows through the shut off valve 4|, a pedestal casing IOI, pipe I02 to the safety valve I03. Fuel flowing through the safety valve I03 enters a pipe I04 which leads to a hydraulically operated fuel and air regulator I06. The fuel then flows through one or more ports I0'I of the regulator I06 and flows from the regulator I06 through a pipe I08 whence it is delivered to a nozzle I09.

The regulator I06 includes a hydraulic operated piston III for opening and closing some of the ports I01 andfor actuating'an air valve 2. The piston III is lifted in response to the pressure of the fuel. If the pressure on the fuel is relatively high, the piston will be moved to a relatively high position, opening more ports I01 and increasing the opening of the air valve. 2. If the pressure on the fuel is decreased, the piston III will lower, cutting off one or more of the ports I01 and partly closing the air valve H2. The pressure on the piston is controlled by the hydrostatic head of the fuel in the pipe connections leading from the valve 44. If there is a large demand for heat from the burner, the

. needle valve 55 of valve 44, actuating through the room thermostat 60, will open sufficiently to maintain a high level of fuel in the vent pipe 99 whereby a relatively high hydrostatic. head of fuel is maintained in the system, which in effect will cause the piston III to be held in raised position. If the demand for heat from the burner decreases, the flow of fuel past the needle valve 55 will be decreased, thereby decreasing the hydrostatic head of fuel in the pipe 9-9 and likewise decreasing the pressure underneath the piston II I whereby it will lower to decrease the flow of fuel and air to the burner.

In the present instance the motor 39 operates constantly to operate constantly a rotary burner indicated generally as H5 and to operate constantly a fan I I6 which fan has dual function of cooling the working parts of the burner and supplying air through the valve II2 to support combustion of the fuel.

The oil delivered to nozzle I09 flows to and is wiped off the end of the nozzle by a sleeve I9I, which is-rotated by shaft I65, and is then thrown radially outwardly through tubes |94. This causes atomization of the fuel and this atomized fuel is mixed at the outer ends of tubes I94 with air. The air for this purpose is forced by the fan I I6 through the valve controlled inlet 200 of the burner and is expelled radially. adjacent the outer ends of tubes |94.

While the apparatus operates ,to intermittently supply fuel to the burner, it is necessary to maintain the burner at a temperature at which the fuel will atomize and vaporize efiiciently. For this purpose there is provided a gas pilot shown diagrammatically at II 8 in Fig. 2. Gas is supplied to the pilot II8 by the pipe line 36 which leads to a pressure regulating valve II9. Gas for the valve |I9 flows through gas line I20 which 4 passes through the pedestal 34 and is connected with a gas line I2| having a shut off valve I22 therein.

If gas is not available for use or if it is desired to use oil for the pilot flame, there is provided the pipe 5| which by-passes or parallels the valves 44 and 45 and the accumulator 46. By

adjusting the valve 52 a quantity of oil can bypass the valves 44 and 45 and accumulator 46 so as to supply a constant quantity of pilot fuel to the burner.

The safety shut off valve I03 is provided with a flexible wall in the form of a corrugated sheet metal disk 232 which carries a ball valve 231. Normally during the operation of the system, the ball valve 23'! is held away from its seat by the flow of oil but in case of an abnormal condition of the system, this .valve is closed upon its seat and is held in this position until manually released. One end of the l ver 245 which is pivoted at 244 is provided with a, weight 246 nor mally tending to rock the lever in a counterclockwise direction A rod 254 at the opposite end of the lever 245 normally holds the weight in its raised position. The rod 254 may be depressed by a handle portion 253. This rod is readily slidable vertically and can be moved upwardly by the weight 246.

A detent 258 in the form of a flat plate is arranged to be slid horizontally over the top of the rod 254 for holding the rod 254 in its lowermost position. This detent 258 is not moved into the latching position until the motor has attained its operating speed and the burner has attained a temperature which will eificiently vaporize the atomized fuel, and the burner is in position in the furnace. Likewise this detent will be removed from its latching position in case of motor failure, decrease in temperature of the burner, or the removal of the heating apparatus from the furnace. The detent 258 is secured to a horizontally disposed rod 259, having its extreme right end slidably mounted within a flange portion 260 of the housing !5!. A spring 26! has one end connected to the detent 258 and the opposite end connected to a stationary part 251 of the burner and the spring normally tends to move the rod 259 and the detent 258 to the left whereby the detent 258 covers the top of the rod 254.

The movement of the rod 259 to the left is counteracted by a thermostat 263 and as long as the temperature of the thermostat is below a predetermined minimum, the thermostat will hold the rod 259 in its extreme right hand position. This thermostat 263 is of the bi-metallic 5 type and is responsive to the temperature of the burner. A rod 265'is carried by the burner and loosely supports a bell crank lever having one arm 266, in the path of movement of the free end of the thermostat, and having a downwardly extending arm 268 arranged to engage a pin 269 secured on the shaft 259. When the temperature of a thermostat is below a predetermined minimum the free end thereof will prevent the clockwise rotation of the arms 266 and (39 268. When the thermostat has been heated to above this minimum temperature it will permit the clockwise rotation of the arms 261 and 268 by the spring 26!. whereby the detent will be pulled over the top of the rod 254 which up to 5 this time is being manually depressed by the arm 253. As soon as the temperature of the thermostat falls below a predetermined minimum, the free end will again rock the bell crank lever to move the rod 259 to the right and release the 7 detent from the top of the rod 254. When this occurs the weight 246 on the lever 245 will cause the closing of the ball valve 231.

A governor 210 also controls the operation of the detent 258. This governor is responsive to the speed of the motor shaft because it is carried by the shaft I65. This governor is arranged to move the detent 258 to the right to release rod 254 when the speed of the motor decreases to a predetermined minimum or stops. When the motor operates at desired speed, the governor permits the spring 26! to move the detent over rod 254.

The detent 258 is also moved to its rod releasing or unlatching position for rod 254 by a weight 283. When the burning apparatus is pushed in position in the furnace, the arm 289 will engage the front wall 290 of the furnace and cause the upward movement of the weight 283 to move the weight so that the detent can be moved to its latching position by the spring 26! after the speed of the motor is increased above a predetermined minimum and when the temperature of the burner is increased above its predetermined minimum. It is apparent that when the heating apparatus is swung away from the furnace so as to move the arm 289 away from contact with the front of the furnace, the weight 283 will overcome the action of the spring 26! whereby the detent will be moved away from above the top of the rod 254.

Thus the oil will be shut ofi to one of two abnormal conditions; namely, that of burner failure or motor failure, and the oil will be shut off by removal of the heating apparatus from the furnace.

To start the burner using gas as the heating element for the burner, the gas valve I22 is moved to the start position and the gas can be ignited at the end of the burner. The gas is permitted to burn a few minutes to permit the heating of the burner and then the burner is placed into the furnace. The motor 39 is then started and the handle 253 is depressed causing the opening of the oil valve 231. After the motor has attained its running speed and after the burner has been heated to above a predetermined minimum temperature, the detent 258 will be moved above the rod 254 and the handle 253 can then be released. In the diagrammatic view (Fig. 2), the gas line I2! is shown as having two branches, one leading to the burner and another leading to the thermostat 263. These two branches are shown merely for the purpose of simplicity of illustration and in actual practice, the thermostat 263 is placed at the extreme right hand end of the burner.

The valve !!2 that controls the flow of air to the burner is pivotally mounted upon the burner shaft 265 and carries a stud 293 which is used for raising the valve II2. This stud is raised by the hydraulic regulator I06. Referring specifically to Figs. 3 to '7 inclusive, the regulator I06 comprises a main body 294 forming a cylinder 295. This body 294 is suitably secured to the burner. A bottom plate 291 which is connected with oil pipe I04 is secured to the bottom of the body 294. Fuel from the pipe I04 passes through the screen 298 and into the cylinder 295 below the piston III. This fuel is arranged to flow through one or more of the ports I01 into a longitudinal passage 299. This passage 299 is connected by a coupling 30! to the pipe I08 leading to the nozzle I09. The piston I! I is lifted by the pressure on the fuel below the same and when a relatively high pressure is present, more of the ports I01 will be opened so as toincrease the flow of fuel through the valve I06. As previously explained the pressure of the fuel is controlled by the hydrostatic head thereof which in turn is regulated by the quantity of fuel permitted to pass the thermal control valve 55. The lowermost port I! is connected with a vertical port 302 and the gasket 303 between the plate 291 and the main body 294 is cut away at this port 302 so that fuel can pass through the lowermost port although the piston I II is in its lowermost position. The purpose of this is to permit a limited quantity of oil to pass to the burner although the pressure on the fuel is at its minimum. The quantity of fuel which can pass through port 302 and about the piston I I I is suflicient to maintain a steady pilot flame at the burner during that phase of the intermittent cycle of operation in which fuel for heating purposes is not delivered to the burner. The passage 299 is connected with the cylinder 295 by a port 304 disposed above bracket also includes an inwardly extending ear 3M upon which is pivotally mounted a lever 3I5. This lever is held in pivotal position by pins SIB. The lever 3I2 adjacent the pivotal point 3I0 is U shaped in cross section and carries a pin 3H3 and the lever 3I5 rests upon this pin and it is arranged to be raised and lowered according to the movement of the pin. When the piston III is raised, the lever 3I2 is rocked upwardly causing the pin 3! to rock the lever 3I5 upwardly and when the piston lowers the lever 3I5 will follow the pin 3I8. In order to prevent the escape of oil from the regulator I06 while still permitting the rocking of the lever 3I5, a flexible bellows 320 is used for sealing the joint where the lever 3I5 extends outside of the regulator. One end of the bellows is secured to a plate 32! and the other end is clamped between a bushing 322 and a nut 323. The bushing 322 is suitably secured to the lever 3I5 as by brazing or soldering. The extreme end of the lever 3I5 engages the under side of the stud 293 of the air valve II2. If the piston III is lifted in response to increase in pressure of fuel more fuel flows to the burner and the lever 3 I is raised to increase the opening of the air valve II2 for increasing the flow of air through opening 200 and thereby maintains the proper fuel mixture proportions. Likewise when the piston I Ii lowers to decrease the quantity of fuel passing through the burner, the lever 3I5 will be lowered permitting the air valve II2 to be lowered to decrease the quantity of air delivered to the burner. With the piston III in its lowermost position, the air valve H2 is entirely closed. However, some fuel continues to flow through the regulator I06 through the port 302 and by the piston II I and in order to supply air to the burner to support combustion of this fuel, a restricted passage for air is provided from the exterior of the housing I5I to the interior through a port 325. The size of this port is permanently adjusted by a valve 326 which can be adjustably fixed in a desired regulated position.

By virtue of the present invention the carburation of the fuel is relatively simple. After the mechanism is once set for proper operation, no adjustments are necessary regardless of the demand for heat from the burner. The regulator I06 maintains proper fuel mixture proportions for efficient operation as long as fuel is supplied to the burner at a rate above a predetermined minimum. Hydro-carbon fuel will be supplied constantly to the burner for room heating purposes only as long as fuel is fed thereto at a rate at which the burner operates efficiently and when the flow of fuel is decreased to such an extent that the burner will not operate with the desired degree of efficiency, the flow of hydro-carbon fuel to the burner ceases temporarily and then the fuel is fed intermittently, and, when fed intermittently, the fuel is fed at such a rate that the burner will operate efficiently. This is accomplished by the provision of the accumulator 46 and the syphonic action thereof. During that phase of the intermittent operation in which fuel is not delivered to the burner for room heating purposes, either gas or liquid fuel is delivered to the burner for maintaining the same at the proper temperature. If gas is not available or if it is not desired to use the gas for pilot purposes, the fuel line 5i which parallels or by-passes the valve MI and accumulator 06, can be used for supplying a limited quantity of fuel to the burner for maintaining the temperature of the burner at the proper degree. The passage 302 in the regulating valve I06 permits suificient liquid fuel to pass, in addition to that which leaks by the piston I I I, to supply fuel for heating the burner when the piston III is in its lowermost position which it assumes during that phase of the intermittent operation in which fuel is not delivered to the burn-er for room heating purposes.

While the form of embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted all coming within the scope of the claims that follow.

1. An oil burning system comprising in combination, an oil burner, air feeding means for supplying air to the oil burner for supporting combustion, fuel feeding means for the oil bumer, means responsive toroom temperature for controlling the pressure of the fuel, control means for causing fuel to be fed continuously to the oil burner when the demand for heat from the oil burner is above a predetermined minimum said control means including a device responsive to a demand for less than said predetermined minimum for causing fuel to be fed intermittently when the demand for heat from said oil burner is less than said predetermined minimum, and means responsive to the pressure of fuel in the fuel feeding means for controlling the quantity of air delivered to the burner.

2. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner, means responsive to variable demands for heat from the burner for correspondingly varying the rate of flow of oil to the burner, an oil reservoir in said oil feeding means intermediate said flow controlling means and burner and including means operable to continuously supply the burner with oil ct varying rates in accordance with the demand for heat when the demand for heat from the burner is above a predetermined minimum and to intermittently supply the burner with oil when the flow of oil to the reservoir is less than said predetermined minimum.

3. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner including a fuel regulating valve and a reservoir intermediatesaid valve and burner, said reservoir having an over-flow outlet leading to the burner and having means coacting with said outlet and operable to withdraw oil intermittently from the reservoir from a level below the overflow outlet. when the rate of flow of oil to the reservoir is less than a predetermined minimum, and a room thermostat for controlling the rate of oil flow to said reservoir.

4. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner including a fuel regulating valve and a reservoir intermediate said valve and burner, said reservoir having an over-flow outlet leading to the burner and having siphon means coacting with said outlet and operable to withdraw oil intermittently from the reservoir from a. level below the overflow outlet when the rate of flow of oil to the reservoir is less than a predetermined minimum, and a room thermostat for controlling the rate of oil flow to said reservoir.

5. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner including a fuel regulating valve and a reservoir intermediate said valve and burner, said reservoir having an overflow outlet leading to the burner, means operable to withdraw oil intermittently from the reservoir from a level below the overflow outlet when the rate of flow of oil to the reservoir is less than a predetermined minithe burner, siphon means operable to withdraw oil intermittently from the reservoir from a level below the overflow outlet when the rate of flow of oil to the reservoir is less than a predetermined minimum, the outlet of the siphon means being connected to the oil feeding means intermediate the reservoir and burner, and a thermostat for controlling said regulating valve.

7. A liquid fuel burning system comprising in combination, a liquid fuel burner, means for feeding liquid fuel to said burner including a thermostatically controlled valve operable to vary the rate of fuel flow in accordance with the heat demand, and a reservoir intermediate said valve and burner having means operable when the rate of fuel feed exceeds a predetermined amount to continuously deliver fuel to the burner and when the rate of fuel feed is less than said predetermined amount to intermittently deliver fuel to the burner.

8. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner, and control means for causing oil to be fed continuously to the burner when the demand for heat from the burner is above a predetermined minimum, said control means including a device responsive to a demand for less than said predetermined minimum for causing oil tobe fed intermittently when the demand for heat from said burner is less than said predetermined minimum.

9. Anoil burning system comprising in combination, an oil burner, oil feeding means for the burner including an oil chamber, means for continuously supplying oil to said burner when the flow of oil to the chamber. is above a certain rate, said chamber having flow control means for intermittently supplying oil to the burner whenthe flow of oil to the chamber is less than said certain rate, and means including a room thermostat for controlling the rate of oil flow to said chamber.

10. An oil burning system comprising in .combination, an oil burner, oil feeding means for the burner, control means for causing oil to be fed continuously to the burner when the demand for heat from the burner is above a predetermined minimum, said control means including a device responsive to a demand for less than said predetermined minimum for causing oil to be fed intermittently when the demand for heat from said burner is less than said predetermined minimum, and pilot oil feeding means for supplying oil to the burner for maintaining the burner at all times above a predetermined minimum temperature.

11. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner, means providing an oil chamber in said fuel feeding means for continuously supplying oil to the burner when the flow of fuel to the chamber is above a certain rate, said chamber having flow control means for intermittently supplying oil to the burner when the flow of fuel to the chamber is less than said certain rate, a room thermostat for controlling the rate of oil flow to said chamber, and pilot oil feeding means paralleling said chamber for supplying oil to the burner for maintaining the burner at. all times above a predetermined minimum temperature.

12. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner, means responsive to variable demands for heat from the burner for correspondingly varying the rate of oil flow to the burner, and control means for causing oil to be fed continuously and at varying rates in accordance with the demand for heat when the demand for heat from the burner is above a predetermined minimum, said control means including a device responsive to a demand for heat less than said predetermined minimum for causing oil to be fed intermittently when the demand for heat from the burner is less than said predetermined minimum.

13. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner, control means for causing oil to be fed continuously to the burner when the demand for heat from the burner is above a predetermined minimum, said control means including a device responsive to a demand for heat less than said predetermined minimum for causing oil to be from said burner is less than said predetermined minimum," and means for igniting the oil when oil is fed to the burner during the intermittent phase of operation of the system.

14. An oil burning system comprising in combination, an oil burner, oil feeding means for the burner, means responsive to variable demandsfor heat from the burner for correspondingly varying the rate of oil flow to the burner, control means for causing oil to be fed continuously and at varying rates in accordance with the demand for heat when the demand for heat from the burner is above a predetermined minimum, said control means including a device responsive to a demand for heat less than said predetermined minimum for causing oil to be fed intermittently when the demand for heat from the burner is less than said predetermined minimum, and means for igniting the oil when oil is fed to the burner during the intermittent phase of operation of the system.

ARTHUR T. BERSEY.

50 fed intermittently when the demand for heat 

